Communications assembly and apparatus

ABSTRACT

A communications assembly, comprising a first device ( 130 ) operable for a public mobile radio network ( 168 ) such as a cellular telephony network, a second device ( 102 ) operable for a private mobile radio network ( 166 ) such as a TETRA network and a communications interface module ( 170 ) configured to provide a communications conduit between said first ( 130 ) and second ( 102 ) devices over a local communications medium is disclosed. The communications interface module ( 170 ) is configured to route a communication originating at said first device ( 130 ) through said communications interface module ( 170 ) to said second device ( 130 ) for transmission over said private mobile radio network ( 166 ). Optionally or additionally a communication initiated at said communications interface module ( 170 ) is routed to said first device ( 130 ) for transmission over said public mobile radio network ( 168 ). The communications interface module ( 170 ) may be further configured to provide a communications conduit between said first ( 130 ) and second ( 102 ) devices over the local communications medium for routing a communication received at said first device ( 130 ) from said public mobile radio network ( 166 ) through said communications interface module to said second device. Further optionally or additionally a communication received at said second device ( 102 ) from said private mobile radio network ( 168 ) may be routed through said communications interface module ( 170 ) to said first device ( 130 ).

FIELD

The present invention relates to a communications assembly andapparatus. In particular, but not exclusively, the present inventionrelates to a communications assembly and apparatus for private mobileradio (PMR) communications systems such as, without limitation, theTerrestrial Trunked Radio (TETRA) system and the P25 or APCO-25 LandMobile Radio system.

BACKGROUND

PMR communications systems, and TETRA in particular, are suitable foruse by emergency services, government agencies, public safety networksand the military where security and reliability of communications is ofparamount importance. PMR systems are also used in commercialenterprises, for example in distributed or wide area locations such aslarge industrial sites, mine environments and the like.

A PMR system often comprises a single main site over which radiocommunications signals are transmitted from a Base Transceiver Station(BTS). Such a site may be termed a “cell” or “main site” and theoperator of such a site may be termed a TETRA Network Operator (TNO).Mobile transceiver units, termed “Mobile Stations (MS)” in the TETRAstandard lexicon, receive and transmit radio communications from and tothe BTS when in the site/cell coverage area. In common with many radiocommunication systems, PMR radio systems such as TETRA can suffer fromgaps in coverage due to a variety of reasons such as the terrain,intervening structures such as buildings and within buildings or tunnelsfor example.

There are also known public mobile radio networks, for example cellulartelephone networks, operated by so-called Mobile Network Operators(MNO). Cellular telephone networks generally support data communicationsservices and are known as second-generation (2G), third-generation (3G)and fourth-generation (4G) with each later generation providing greaterdata communications services than the previous generation.

Due to their generally lower operating frequencies and narrowercommunications channels PMR systems often have better rural coveragethan cellular telephone networks, however data bandwidths are invariablylower than can be achieved by the public networks.

Aspects and embodiments of the present invention were devised with theforegoing in mind.

SUMMARY

Viewed from a first aspect there is provided a communications assembly,comprising:

-   -   a first device operable for a public mobile radio network;    -   a second device operable for a private mobile radio network; and    -   a communications interface module configured to provide a        communications conduit between said first and second devices        over a local communications medium for routing:    -   a communication originating at said first device through said        communications interface module to said second device for        transmission over said private mobile radio network; and        optionally or additionally    -   a communication initiated at said communications interface        module to said first device for transmission over said public        mobile radio network.

Viewed from a second aspect there is provided a communications assembly,comprising:

-   -   a first device operable for a public mobile radio network;    -   a second device operable for a private mobile radio network; and    -   a communications interface module configured to provide a        communications conduit between said first and second devices        over a local communications medium for routing:    -   a communication received at said first device from said public        mobile radio network through said communications interface        module to said second device; and optionally or additionally    -   a communication received at said second device from said private        mobile radio network through said communications interface        module to said first device.

The communications interface module provides for a first device such asa Smartphone to collaborate with a second device such as a PMR terminalwithout the need for development or modification of a standard second(PMR) device. Collaboration allows use to be made of the availablenetwork services through the general superior Man Machine Interface of aSmartphone compared to a PMR terminal.

The communications interface module of the second aspect may alsoprovide a communications conduit between said first and second devicesover a local communications medium for routing:

-   -   a communication originating at said first device through said        communications interface module to said second device for        transmission over said private mobile radio network; and        optionally or additionally    -   a communication initiated at said communications interface        module to said first device for transmission over said public        mobile radio network. Such an arrangement supports the        connection of the first and second devices using a radio        technology which can then provide for interworking of the        devices.

For applications requiring secrecy the communications interface moduleis configured to provide a secure communications conduit between saidfirst and second devices over said local communications medium. Theinterface module can be developed to provide a level of securityacceptable to different user markets without the need for customdevelopments of the second (PMR) device. This may be very important foremergency services, police and military use for example.

Typically, the secure communications conduit employs commercial standardencryption which would provide a relatively low cost solution. However,the secure communications conduit may employ encryption approved forprotection of government protectively marked material if necessary. Byhaving the interface module, it is possible for specific government orother standards to be followed without the need for customisation of thesecond (PMR) device itself.

Suitably, the first device is configured to establish a secure mutuallyauthenticated session to said communications interface module prior tosaid secure communications conduit being established. By layering onadditional authentication at the application layer of the first device(generally a more easily adapted device such as a smartphone) it becomespossible to provide extra assurance of the link for more sensitive usermarkets.

The first device may be configured to determine one or more networkcapabilities of respective said private mobile radio network. Forexample, the one or more network capabilities may include one or more ofthe following: signal quality, communications capability and bandwidth.Once the devices are connected it then becomes possible for a widerawareness of combined communication capabilities to be established. Anumber of factors can be used to influence the best choice of networkfor any given communication, these may include the quality of the signalwhich will directly affect the communications performance, the availablecommunications capability which will affect what can be communicated andthe bandwidth which can impact performance for the both the user andother users of the system.

Optionally or additionally, the first and/or second devices areconfigured to determine respective geographic location, for example byway of the global positioning satellite (GPS) system and/or based uponradio network access point information. Both the Smartphone and the PMRdevice may have GPS capability and so both facilities should be used todetermine GPS position in case one or other facility is working betterthan the other.

Optionally, the first device may determine network information from acentral network application for said public telecommunications systemand/or said private mobile radio system.

By communicating with the central network application additionalintelligence or guidance can be accessed to make better decisions as towhat communications channel should be used. An example of this may beinstructing the second (PMR) device to switch Talkgroups when moving toa different area, or guiding the device to select the public mobileradio network for less critical group communications during times whenthe important communications traffic may be high, such as during a majoremergency incident.

Suitably, location information for respective first and second devicesis compared on said first device to identify the best location fix asthe first device may have greater processing power and/or be capable ofrunning applications. Also the two devices are likely to be worn indifferent places on the body and may have different sensitivities withregards to GPS so it makes sense to determine if one or other of the GPSdevices is performing better than the other.

The first device may be configured to:

-   -   retrieve information concerning said one or more network        capabilities from said second device via said communications        interface module;    -   select said one or other of said public mobile radio network or        said private mobile radio network for transmitting or receiving        said communication based on said one or more network        capabilities and/or said respective geographic locations and/or        said network information. By making the central application        aware of the communications capabilities available to the first        and second devices end user it is possible to route outbound        communications from the network to the most appropriate device        over the most appropriate network at any given time.

The first device may be configured to communicate said location fix torespective network applications over a selected one of said publicmobile radio network or said second private mobile radio network.Depending on the existing network conditions it may be appropriate toroute the user location information back over different networks, forexample if the PMR network is suffering from control channel congestionit may be better to provide the update over the public network.

The first and second device may be configured to periodically determinesaid one or more network capabilities and/or said geographic location toprovide updated information thereon; and

-   -   said first device may be configured to select said one or other        of said public mobile radio network and said private mobile        radio network for communications based on said updated        information; and optionally    -   said first device may be configured to periodically determine        said network information to provide updated network information        and select said one or other of said public mobile radio network        and said private mobile radio network based on said updated        network information. By periodically checking current        capabilities and exchanging the information with the central        network application it becomes possible to dynamically tune        communications across the network to ensure the best possible        experience for the user community as a whole.

Suitably, the first device is configured to communicate informationidentifying said selected one of said public mobile radio network and/orsaid private mobile radio network to central network applications. Asthe first device (eg Smartphone) has the most processing capability itcan be configured to more effectively process the availablecommunications capabilities and send that information back to thenetwork.

The first device may be configured to provide a second devicecommunications inhibit signal to said communications interface moduleresponsive to selection of said public mobile radio network forcommunications, said communications interface module responsive to saidsecond device communications inhibit signal to inhibit communication viasaid second device and private mobile radio network.

Typically, the communications interface module may be responsive to saidsecond device communications inhibit signal to inhibit an impedancechange on a microphone circuit of said second device since the impedancechange is what signals a PTT communication for a second device such as aTETRA terminal.

Suitably, the first device is configured to provide a user interfaceoperative to generate control signals for said second device and routesaid control signals to said second device via said communicationsinterface module. As the second (PMR) device is often worn in a positionwhich makes it difficult to be operate and also as the man machinesinterface on the second (PMR) device tends to have a limited capabilityboth in screen size and keyboard, access to the second (PMR) devicefunctionality from the first (smartphone) device interface is bothbeneficial and effective. In addition through use of the first(smartphone) device interface the user interface requirements of thesecond (PMR) device are reduced which allows for cheaper and more robustdevices to be used.

The first device may be configured to provide a user display operativeto receive control messages from said second device and route saidcontrol signals from said second device via said communicationsinterface module. Thus, the generally better user interface of a firstdevice such as a smartphone can be used. For example, whencommunications such as text messages are received by the PMR device theycan be passed to the smartphone which provides a better man machineinterface for presentation to the user.

The communications interface module may provide a common audio interfacefor communications over said public mobile radio network or said privatemobile radio network. By having a common audio interface, communicationsreceived from either network can be presented in the most convenient way(either headset or remote speaker microphone) which means the firstdevice (smartphone) can continue to be used as the data interface or canbe left securely in a pocket when receiving calls.

Suitably, the communications interface module provides a push to talkswitch for group communications over said public mobile radio network orsaid private mobile radio network. By having an external push to talkswitch the user does not need to be aware of which networks areavailable as the device determines the most appropriate network androutes the communication accordingly.

Preferably, the communications interface module is a separate articlefrom said first and second device. By developing the external device thetime and cost constraints associated with developing the capabilitieswith the second (PMR) device can be avoided, this also simplifies thevariations in configurations required on the first device (smartphone).

The communications interface module may be configured to interengagewith said second device to provide electrical connection for electroniccommunication between said communications interface module and saidsecond device. By connecting directly to the second (PMR) deviceconcerns over weaknesses in radio interfaces for simple devices such asBluetooth® can be overcome. Furthermore, the interface module may besupported by the second device through mechanical engagement.

The communications interface module may receive power from said seconddevice. By taking power from the second (PMR) device cost, size, weightand complexity of the interface module can be minimised.

Advantageously, the communications conduit is wireless. Thecommunications conduit may comprise a wireless communication betweensaid communications interface module and said first device. Keeping thecommunications wireless between the first device (smartphone) and theinterface module avoids wires that could provide awkward to manage andin the worst case may be dangerous to a user in violent situations.

Suitably, the communications interface module is coupled to a microphoneand/or an earpiece for said second device. By presenting the audio fromthe first device (smartphone) to the interface module it becomespossible to continue to use the first device (smartphone) as a datainterface whilst in a call and also allows the first device (smartphone)to remain in a pocket when receiving a call.

The communications interface module may be coupled to said microphoneand/or said earpiece via a wired connection and/or said communicationsinterface module is integrally formed with a microphone and/or aspeaker. By providing a flexible common audio interface the bestconfiguration can be selected based upon the user requirements which mayeither be headset or remote speaker microphone. Additionally, audio fromthe two devices can be combined, presented in parallel, or muted throughconfiguration.

Viewed from a third aspect there is provided a communications interfacemodule for a communications assembly according to any of the precedingdefinitions. A separate communications interface module allows for backcompatibility with existing second devices such as TETRA and other PMRterminals.

Viewed from a fourth aspect there is provided a communications interfacemodule configured to provide a communications conduit over a localcommunications medium between a first communications device operativefor a public mobile radio network and second communications deviceoperative for a private mobile radio network for routing:

-   -   a communication originating at said first device through said        communications interface module to said second device for        transmission over said private mobile radio network; and        optionally or additionally    -   a communication initiated at said communications interface        module to said first device for transmission over said public        mobile radio network.

LIST OF FIGURES

A specific description of one or more embodiments in accordance with thepresent invention will now be described, by way of non-limiting exampleonly, and with reference to the accompanying drawings in which:

FIG. 1 is a schematic illustration of a network including an assembly inaccordance with an embodiment of the present invention;

FIG. 2 is a schematic illustration of a communications interface modulein accordance with an embodiment of the present invention;

FIG. 3 is a flow diagram schematically illustrating the operational flowin an embodiment during power up and connection of a TETRA mobilestation with a Smartphone;

FIG. 4 schematically illustrates the operational flow in an embodimentof the present invention to establish awareness of location;

FIG. 5, schematically illustrates the operational flow in an embodimentof the present invention during a group talk operation;

FIG. 6 schematically illustrates the operational flow in an embodimentof the present invention during an individual call; and

FIG. 7 is a schematic illustration of the operational flow in anembodiment of the present invention during data communications.

DESCRIPTION

Embodiments in accordance with the present invention will now bedescribed with reference to FIG. 1 which illustrates an arrangement 100including a TETRA communications network 166, typically used in the UKby the emergency services amongst other users, and a cellular telephonynetwork 168. A TETRA mobile station 102 comprises the usual elements ofa telecommunications device including a display 104, a radio-frequencymodule 106, and antenna 108, a digital signal processing module 110 andbaseband processing module 112. Also included are a keypad 114 and anaudio module 116.

Each of the various modules perform their usual functions for a TETRAmobile station which in short comprises the baseband processor 112controlling the general activities of the terminal device includinginterrogating the keypad 114 and arranging for the presentation ofinformation on display 104. The digital signal processor 110 encodesaudio signals to be transmitted via the radio-frequency unit 106 anddecodes signals from the radio-frequency unit 106.

The audio module 116 receives analogue audio signals from microphone 118and inputs them to an analogue to digital converter within the audiomodule 116 for forwarding to digital signal processor 110. Digitalsignals processed by digital signal processor 110 are forwarded to audiomodule 116 into a digital to analogue converter within the audio module116 which outputs an analogue audio signal to earpiece 120.

The TETRA mobile station 102 also includes a Peripheral EquipmentInterface (PEI) module 122. The PEI is defined in the TETRA standard ETS300 392-5 and defines the data and control signals which may be sent toand received by the TETRA mobile station 102 from external sources inorder to manage and/or control the TETRA mobile station 102 and/or theexternal source.

The TETRA mobile station 102 may communicate over a radio-frequencychannel with a base station 154 of the TNO network 166. The base station154 is coupled to a TETRA radio access node 156 which in turn is coupledover a trunk connection to a voice control application 162 controlled bythe TNO. The voice control application in the TNO network infrastructureis configured to monitor i.e. to be aware of, all of the available radiopaths available to the TETRA mobile station 102 including (but notlimited to) the TETRA network 166, cellular telephony network 168, localnetworks such as WiFi etc and then routes voice communications to theTETRA mobile station 102 based upon a determination of the mostappropriate path. The radio access node 156 is also coupled over a trunkconnection to a data application 164 of the cellular telephony network168 controlled by the MNO. Data application 164 is also configured tomonitor available radio paths and to choose the one most suitable fordata communications.

A public mobile radio network data capable device 130, such as a smartphone for a cellular telephony network 168 comprises the usualfunctional modules incorporated in such devices. Examples of smartphones range from predominantly voice telephony devices incorporating aWorld Wide Web browser application capable of connection to the WorldWide Web through to devices which incorporate the features of a PersonalDigital Assistant (PDA) and a suite of data applications includingapplications for communicating with the World Wide Web as well astelephony services.

In the illustrated embodiment, the smart phone device 130 incorporates atouch screen display 132 a radio-frequency unit 136 and radio-frequencyantenna 136. Device 130 also includes a digital signal processor 138 anda baseband processor 140. Also included is a screen driver 142 formanaging what is displayed on the touch screen 132 and handling userinput made via the touchscreen 132. Smart phone device 130 also includesapplications 144, such as middleware applications and clientapplications, suitably stored in persistent memory, for managingcommunications with the communications interface module 170. Themiddleware performs a number of functions including the following (i)establishment of secure pairing with the TETRA mobile station 102 viathe communications interface module 170 (ii) collection and processingof available network connectivity from all available networks forpresentation to supported applications on the Smartphone device (iii)providing a path to enable applications on the Smartphone device topresent the Man Machine Interface (MMI) of the TETRA mobile station 102.

The audio module 146 is coupled to both the microphone 148 andloudspeaker 150; and receives digital signals from DSP 138 into adigital to analogue converter for output as analogue signals toloudspeaker 150 and vice versa receives analogue signals from microphone148 into an analogue to digital converter for input to DSP 138. Smartphone device 130 also includes a local wireless communications module152 which includes a Bluetooth® communications part and a Wi-Fi part.

The smart phone device 130 may communicate over a radio-frequencychannel with a base station 158 of the MNO network 168. The base station158 is coupled to a MNO radio access node 160 operable for datacommunications on one or more of a second-generation, third-generationand fourth-generation cellular communications protocol, and which inturn is coupled over a trunk connection to a data middleware application164 controlled by a data service provider. The data middlewareapplication in the MNO network infrastructure monitors, i.e. is awareof, all of the available radio paths available to the user including(but not limited to) the cellular telephony network 168, TETRA network168, local networks such as WiFi etc and then routes data communicationsto the user based upon the most appropriate path.

The radio access node 160 is also coupled over a trunk connection tobearer aware, and voice control module 162 of the TNO.

FIG. 1 also illustrates a communications interface module 170 arrangedto interface with TETRA mobile station 102 and smart phone device 134for communicating PEI signals between them. The illustratedcommunications interface module 170 also includes a button, 172, toinitiate a Push To Talk (PTT) communication. In the described embodimentthe communications interface module 170 includes “curly cable” 117 whichis coupled to microphone 118 and earpiece 120. Having the microphone 118and headset 120 connected to the TETRA terminal device, albeit viacommunications interface module 170, by a curly cable is a typicalphysical configuration for TETRA devices, although such an arrangementis not essential and the microphone and/or speaker may be mounted withinthe terminal device 102 itself or directly in the communicationsinterface module 170.

In FIG. 2, there is schematically illustrated the communicationsinterface module 170. In the described embodiment the communicationsinterface module 170 is a plug-in module to TETRA mobile station 102. Asimple printed circuit connector element 202 is used to provide aconnections interface between the communications interface module 170and TETRA mobile station 102. Communications interface module 170comprises a PTT module 204 configured to receive a PTT initiation signalgenerated responsive to actuation of button 172, and audio interface 206including an analogue to digital and digital to analogue converter, alocal processor 208 for controlling the operation of the communicationsinterface module 170 and a local network communication module 210including Bluetooth® wireless communications functionality, including aBluetooth® antenna. The device communications interface module may bebased upon a processor such as Texas Instruments AMM355x with associatedBluetooth interfaces.

One or more embodiments include the TETRA mobile station 102 and smartphone device 130 configured so that they may be in co-operativecommunication with one another through the communications interfacemodule 170 and consequently both the TETRA mobile station 102 and smartphone device 130 may be in operation at the same time. Thecommunications interface module 170 Bluetooth® identity is paired withthe Bluetooth® identity of the smart phone device 130 so that they cancommunicate with each other when initialised. This does not preclude oneor other of the TETRA mobile station 102 and smart phone device 130being operated independently of the other device.

FIG. 3 schematically illustrates power up of respective TETRA mobilestation 102 and smart phone device 130 and their communicationsconnection. The electrical interface for the TETRA mobile station 102which includes the PEI module 122 and audio external headset interfaceis coupled to the communications interface module 170 when it is pluggedinto the TETRA mobile station 102. The audio external headset interfaceprovides for audio signals to be coupled to the microphone 120 andearpiece 118 of a headset connected to the communications interfacemodule 170. Power up of the TETRA mobile station 102 also provideselectrical power over its electrical interface 122 to the electricalconnector 202 of the communications interface module 170 in order topower the interface module. Responsive to the receipt of power, thelocal processor 208 boots up and initialises the PTT control module 204,audio AD/DA interface module 206 and local network communications module210. In response to initialisation the local network communicationmodules 210 activates its Bluetooth® wireless communicationsfunctionality thereby making itself discoverable to other Bluetooth®enabled devices within wireless range.

The smart phone device 130 automatically boots up the communicationsinterface middleware application 144 which initialises a search for apaired communications interface module 170 through the Bluetoothinterface 152. Once the paired communications interface module 170 hasbeen identified a Bluetooth connection request 304 is transmitted fromsmart phone device 130 over the Bluetooth interface 302 to thecommunications interface module 170. The Bluetooth® circuitry in thelocal network communications module 210 responds to the Bluetooth®connection request 304 after confirming the identity of the smart phone130 in accordance with security protocols as defined by the Bluetoothstandard. Additional application level security may also be providedbetween the middleware on the Smartphone and the application on thecommunications interface module if more secure connectivity is deemednecessary. This security could be provided using industry standard X509certificate exchange or other security standard. The local networkcommunications module 210 establishes an encrypted Bluetooth® path forcommunication with the smart phone 130 and sends a Bluetooth® connectionaccepted message 306.

Following setting up of an encrypted communications path between thesmart phone device 130 and communications interface module 170 thecommunications interface middleware application 144 issues a PEIconnection request 308 to establish a communications connection to theTETRA mobile station 102 through the PEI of the communications interfacemodule 170. The TETRA mobile station 102 sends a PEI connectionacknowledgement message 310 back to the smart phone device 130 tocomplete establishment of the communications connection. Smart phonedevice 130 utilises the communications connection with the TETRA mobilestation 102 to make the PEI available to applications 144, such asclient applications, on the smart phone device. One example of theclient application is the remote presentation of the TETRA mobilestation 102 Graphical User Interface (GUI) to the Smartphone interface.This GUI will provide a user with an interface to make changes toTalkgroups on the TETRA mobile station 102 without the need to accessthe TETRA mobile station 102 itself.

Additionally, responsive to power up the TETRA mobile station 102connects to the TETRA network 166 via base station 154 and the smartphone device 130 connects to the cellular telephony network 168 over astation 158. The TETRA mobile station 102 receives network informationrelating to various network capabilities such as signal quality andavailable capacity, e.g. network congestion, in the network. Likewise,the smart phone device 130 receives information concerning signalquality and available bandwidth within the cellular telephony network,and other local network intelligence information from the centralnetwork application for improving the smart phone device's ability tomake communications path decisions. Additionally, the TETRA mobilestation 102 and smart phone device 130 may derive location information.The location information may be derived from an awareness of the basestations from which they may receive signals and, if at least one orother of the devices has a Global Positioning Satellite (GPS) receiver,based on GPS positioning signals. In general, the TETRA mobile station102 includes a GPS receiver since location of emergency servicespersonnel is important information for the emergency services.

FIG. 4 schematically illustrates the operational flow between the TETRAmobile station 102 and smart phone device 130 establishing an awarenessof location. A smart phone device client application, which may eitherbe a separate program or one that forms part of the middleware, uses thePEI connection to send a message 320 over the Bluetooth interface 302,via the communications interface module 170 and through the electricalinterface 122 to the TETRA mobile station 102 requesting informationconcerning the GPS location, voice and data service availability overthe TETRA network, the current activity of the TETRA mobile station andthe Talkgroup to which the TETRA mobile station 102 is currentlyattached or active on. TETRA mobile station 102 responds to the requestby sending a message 322 with the location and service information backto the smart phone device 130. Once the application on the Smartphonehas established the best location fix it updates the infrastructure overthe most appropriate network (bearer) path. The most appropriate networkpath is selected based upon a combination of local configurationparameters and dynamic parameters optionally updated from theinfrastructure. This process allows dynamic mitigation of potentialnetwork congestion based upon conditions that may only be known to theMNO and/or the TNO network infrastructure.

The smart phone device 130 compares the information concerning servicecapability of the TETRA network 166 received from the TETRA mobilestation 102 with the service capability data received from the cellulartelephony network 168 to determine which network provide the bestcommunications capability. The smart phone device 130 will periodicallycompare the information concerning service capability between thenetworks so that any changes can be compensated for, for example byselecting the other network should the currently selected network bedetermined as having a lower capability and the other network.

For example, if the most suitable network is considered to be the TETRAnetwork 166 then the smart phone device 130 updates any infrastructureapplications 162, 164 such as command and control systems withinformation concerning network capability over the TETRA network 166 andalso sets up a communications connection through the communicationsinterface module 170 to the TETRA mobile station 102 such thatcommunications originating with the smart phone device 130 may be routedthrough the TETRA mobile station 102 and over the TETRA network 166.Conversely, if the cellular telephony network 168 is determined to havethe greater capability the smart phone device 130 configures itself touse the cellular telephony network 168 for communications. Havingdetermined which network has the greater communications capability, thesmart phone device 130 transmits the GPS location of one or other of theTETRA mobile station 102 and smart phone device 130.

An aspect of TETRA radio systems, and indeed in some other PMR radiosystems, is the ability for a TETRA mobile station to communicate withseveral other mobile stations at once. This may be described as grouptalking since a group of mobile stations are linked such that when anyone of them initiates a group communication all the other mobilestations in the group that are within range of the network receive thegroup communication. This feature is often termed “Push To Talk” andgoes by the acronym “PTT”. Within the TETRA community the group ofmobile stations is known as a “Talkgroup”.

Referring now to FIG. 5, there is a schematic illustration of theoperational flow between TETRA mobile station 102 and smart phone device130 during group calling (i.e. a PTT operation). The client applications144 on the smart phone device 130 are also configured to manageTalkgroup (PTT) communications. Cellular PTT applications forSmartphones are already available and the application on the smartphonedevice 130 may be configured to provide similar functionality. The PTTcall is initiated by activating the PTT switch 172 on the communicationsinterface module 170. The audio and PTT signaling are taken from theheadset and PTT switch connected via the communications interface module170 and converted to Internet Protocol signals for transmission over thepublic mobile radio network. Within the cellular telephony networkcommunications are linked via a gateway to integrate the PTT groupcommunications with the central TETRAnetwork.

A Talkgroup is defined on the TETRA mobile station 102 by associatingvarious mobile station identities within the group to form theTalkgroup. Talkgroup identities, known as Group Short SubscriberIdentity (GSSI), are stored in the TETRA mobile station 102 and may begenerated and set up using TETRA mobile station 102. In the illustratedembodiment smart phone device 130 sends a message 340 via the PEIinterface interrogating the TETRA mobile station 102 for the currentTalkgroup information, for example the network identities of individualmobile stations within the Talkgroup. The Talkgroup is returned to thesmart phone device 130 and may consist of a label identifying aparticular Talkgroup and/or a logically grouped list of mobile stationidentities forming the Talkgroup or some other representation of theTalkgroup.

The client application displays the Talkgroup 340 via a graphical userinterface on the touchscreen display 132 of the smart phone device 130.Client application 144 is also configured to allow a user of the smartphone device 130 to modify the displayed Talkgroup through the graphicaluser interface. Modifications made to the Talkgroup via the graphicaluser interface are communicated over the communications interface module170 to the TETRA mobile station 102 via the PEI 122 to modifycorrespondingly the Talkgroup stored in the TETRA mobile station 102.Optionally or additionally, modifications to the Talkgroup may beinstructed over the air from the cellular telephony network 168 operatorand/or a communication from the TETRA network 166 operator.

Responsive to actuation 342 of the PTT button 172, smart phone device130 middleware application 144 compares the current network capabilityof the TETRA network 166 received from TETRA mobile station 102 with thecurrent network capability for the cellular telephony network 168 todetermine which network has the best communications capability. Thecomparison may be made on network capability information that has beenperiodically updated, or the smart phone device 130 may instruct TETRAmobile station 102 to update network capability information and providethe updated information to the smart phone device 130; the smart phonedevice 130 also obtaining network capability information from thecellular telephony network 168.

In the described embodiment, the default network for Talkgroupcommunications is the TETRA network 166 because Talkgroup communicationsare a common mode of communication within a PMR network such as TETRA,in particular when used by the emergency services. Thus, PTT signallingis routed to the TETRA mobile station 102 as a default 344. On the otherhand, if the Push To Talk client application 144 of the smart phonedevice 130 makes a determination that the cellular telephony network 168(MNO) has greater network capability or is more suitable, then the smartphone device middleware 144 instructs the communications interfacemodule 170 to route PTT signaling, 346, to the PTT client application ofsmart phone device 130. PTT signaling is generally triggered on TETRAmobile station 102 devices by changing the impedance on the microphonecircuit and therefore when the cellular telephony network is chosen, thecommunications interface module 170 is configured by way of signalinggenerated by the smart phone device 130 to intercept the impedancechange to prevent activation of PTT signaling on the TETRA mobilestation device 102 and instead generate signaling that can betransmitted to the smartphone device 130 over the Bluetooth® interface.If the PTT signaling is directed to TETRA mobile station 102 then, 348,the audio interface 206 is connected between the common headset 118/120and the TETRA mobile station 102. On the other hand, if the PTTsignaling is directed to the smart phone device 130 then, 350, the audiointerface 206 is connected between the common headset 118/120 and thesmart phone device 130.

In the event that the smart phone communications interface middlewareapplication 144 determines that the cellular telephony network 168 (MNO)should be used for communications a message is automatically sent to thedata application 164 in order to ensure that received PTT communicationsare routed via the cellular telephony network 168 (MNO) to the smartphone device 130 and presented to the common headset 118/120 of thecommunications interface module 170.

The operational flow for an individual call in accordance with anembodiment is schematically illustrated in FIG. 6. For the describedembodiment, individual calls are setup using a phonebook stored in thesmartphone device 130, since the smart phone has a more flexible andeasier to use graphical user interface than the user interface typicallyprovided for TETRA mobile station 102. The user selects a contact fromthe phonebook and initiates the call, 360, using the graphical userinterface of the smart phone device 130. The phone book on thesmartphone device 130 is an application that is configured tocommunicate any call setups via the middleware on the device 130. Themiddleware on the device 130 then routes the call to the mostappropriate network. The middleware also handles any additional routingdigits if required by the TETRA network or cellular telephony network.

Again, smart phone device 130 middleware application 144 compares thecurrent network capability of the TETRA network 166 received from TETRAmobile station 102 with the current network capability for the cellulartelephony network 168 to determine which network has the bestcommunications capability. The comparison may be made on networkcapability information that has been periodically updated, or the smartphone device 130 may instruct TETRA mobile station 102 to update networkcapability information and provide the updated information to the smartphone device 130; the smart phone device 130 also obtaining networkcapability information from the cellular telephony network 168. Thesmart phone device 130 middleware application 144 compares the networkcapability of the TETRA and cellular networks to determine which has thebetter capability and should be used

Depending upon which network is selected by the middleware application144, the individual call is our setup over the cellular telephonynetwork 168 (MNO bearer) or the TETRA network 166. For calls originatingfrom the network, the communications control in the network, i.e. theTETRA network, will select whether not use the TETRA network or cellulartelephony network to transmit the call. Additionally, the smart phonedevice 130 can stay in a low-power mode until it is signalled to respondto an incoming voice calls over the cellular telephony network. CallingLine Identification (CLI) may also be presented by the smart phonedevice 130 graphical user interface.

If the call is determined to be set up, 362, over the cellular telephonynetwork 168 (MNO network) the call is initiated in the usual manner fromthe smart phone device 130. Accordingly, the audio module 206 isconnected, 366, between the common headset 118/120 and smartphone 130.If the call is determined to be set up, 364, with the TETRA network 166,the smart phone device 130 communicates call setup data and voice dataover the Bluetooth® interface 302 with the and via the PEI 122 to theTETRA mobile station 102. The TETRA mobile station 102 then initiatesthe call over the TETRA network 166. Accordingly, the audio module 206is connected, 368, between the common headset 118/120 and the TETRAmobile station 102. Optionally, in the event of covert operations theaudio could also be presented to the smart phone device 130 such that auser could be receiving communications over the TETRA network yet appearto be using a cellular telephony network.

The middleware application 144 for determining which network to use maybe configured to prefer calls to be sent over the TETRA network sincethat will avoid the call charges levied for the public cellulartelephony network.

For the described embodiments, data communications utilise the smartphone graphical user interface for the simple reason that the graphicaluser interface available on the smart phone provides for flexible dataactivities, for example web browsing. The smart phone data applicationand 144 will be configured to use the common headset 118/122 providesfor either voice recognition and/or audio response to an end user. Forinbound data the smart phone device 130 may remain a low-power state andonly activate the cellular telephony network 168 (MNO bearer) when it issignalled to do so over the TETRA network 166. The data path selected iscontrolled by middleware application 144 in the smartphone device 130and is configured to choose the best network available for the datacommunication required. The selection of data bearer will follow similarcriteria to voice communications i.e. an algorithm based on localconfiguration, network availability, network congestion and knownevents, however additionally available data bandwidth will also be anadditional criteria

FIG. 7 is a schematic illustration of the operational flow between theTETRA mobile station 102 and the smart phone device 130 for datacommunications. A data client application 144 running on the smart phonedevice 130 issues a request for a data network service to thecommunications interface middleware for a data communications networkservice based upon the periodic network capability information receivedfrom the TETRA network 166 and the cellular telephony network 168 orupon updated information requested responses to the request for a datanetwork service. The communications interface middleware select the mostappropriate data network dependent upon the received network capabilityinformation. The client data application 144 is informed of the datanetwork selection made by the middleware and the data client applicationsends data via the communications interface middleware, 380, to thecommunications interface module 170.

If the cellular telephony network 168 (MNO bearer) is selected then datais sent over the network, 382, direct from the smart phone device 130.Optionally, and audio response may be sent, 386, to the common headset118/120. Further optionally or additionally, audio signals may betransmitted from the common headset 118/120 for voice recognitioncontrol of smartphone device 130. On the other hand, if the TETRAnetwork 166 is selected the middleware application 144 establishes adata connection over the Bluetooth interface 302® to the communicationsinterface module 170 and then via the PEI 122 to the TETRA mobilestation 102 from where it is transmitted over the TETRA network 166.

In view of the foregoing description it will be evident to a personskilled in the art that various modifications may be made within thescope of the invention.

Although embodiments in accordance with the present invention have beendescribed with reference to a communications interface module physicallyseparate from the TETRA mobile station 102 and the smart phone device130, the communications interface module may be incorporated in one orother of the devices, more particularly within the TETRA mobile station102. Furthermore, the term mobile station, base station and acronym BSare not intended to restrict embodiments in accordance with theinvention to systems, standards or protocols using such terminology butare generally intended to refer to communications equipment serving ageographic area with radio communications coverage providing downlinkand/or uplink communications.

The communications interface module 170 has been described as having awireless (Bluetooth®) local network connection to the smart phone device130 but other wireless communications protocols may be utilised such asWi-Fi. Optionally or additionally, the communications interface module170 may be coupled to the smart phone device 130 by a wired connectionsuch as a curly cable.

Although the communications interface module 170 has been described ashaving a wired connection to a microphone and earpiece, embodiments maybe conceived in which the microphone and a speaker are integrated in thecommunications interface module 170 itself. Additionally or optionally,the communications interface module 170 may also include a “talk”initiation switch for initiating “one-to-one” communications from thecommunications interface module 170 over the public mobile network.

Insofar as embodiments of the invention described above areimplementable, at least in part, using a software-controlledprogrammable processing device such as a general purpose processor orspecial-purposes processor, digital signal processor, microprocessor, orother processing device, data processing apparatus or computer system itwill be appreciated that a computer program for configuring aprogrammable device, apparatus or system to implement the foregoingdescribed methods, apparatus and system is envisaged as an aspect of thepresent invention. The computer program may be embodied as any suitabletype of code, such as source code, object code, compiled code,interpreted code, executable code, static code, dynamic code, and thelike. The instructions may be implemented using any suitable high-level,low-level, object-oriented, visual, compiled and/or interpretedprogramming language, such as C, C++, Java, BASIC, Perl, Matlab, Pascal,Visual BASIC, JAVA, ActiveX, assembly language, machine code, and soforth. A skilled person would readily understand that term “computer” inits most general sense encompasses programmable devices such as referredto above, and data processing apparatus and computer systems.

Suitably, the computer program is stored on a carrier medium in machinereadable form, for example the carrier medium may comprise memory,removable or non-removable media, erasable or non-erasable media,writeable or re-writeable media, digital or analog media, hard disk,floppy disk, Compact Disk Read Only Memory (CD-ROM), Company DiskRecordable (CD-R), Compact Disk Rewriteable (CD-RW), optical disk,magnetic media, magneto-optical media, removable memory cards or disks,various types of Digital Versatile Disk (DVD) subscriber identifymodule, tape, cassette solid-state memory. The computer program may besupplied from a remote source embodied in the communications medium suchas an electronic signal, radio frequency carrier wave or optical carrierwaves. Such carrier media are also envisaged as aspects of the presentinvention.

As used herein any reference to “one embodiment” or “an embodiment”means that a particular element, feature, structure, or characteristicdescribed in connection with the embodiment is included in at least oneembodiment. The appearances of the phrase “in one embodiment” in variousplaces in the specification are not necessarily all referring to thesame embodiment.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Further, unless expressly stated to the contrary,“or” refers to an inclusive or and not to an exclusive or. For example,a condition A or B is satisfied by any one of the following: A is true(or present) and B is false (or not present), A is false (or notpresent) and B is true (or present), and both A and B are true (orpresent).

In addition, use of the “a” or “an” are employed to describe elementsand components of the invention. This is done merely for convenience andto give a general sense of the invention. This description should beread to include one or at least one and the singular also includes theplural unless it is obvious that it is meant otherwise.

The scope of the present disclosure includes any novel feature orcombination of features disclosed therein either explicitly orimplicitly or any generalisation thereof irrespective of whether or notit relates to the claimed invention or mitigate against any or all ofthe problems addressed by the present invention. The applicant herebygives notice that new claims may be formulated to such features duringprosecution of this application or of any such further applicationderived therefrom. In particular, with reference to the appended claims,features from dependent claims may be combined with those of theindependent claims and features from respective independent claims maybe combined in any appropriate manner and not merely in specificcombinations enumerated in the claims.

The invention claimed is:
 1. A communications assembly, comprising: afirst device communicatively coupled to a public mobile radio network; asecond device communicatively coupled to a private mobile radio network;and a communications interface module configured to provide acommunications conduit between said first and second devices over alocal communications medium for routing: a communication originating atsaid first device through said communications interface module fortransmission over said private mobile radio network via said seconddevice; and a communication initiated at said communications interfacemodule for transmission over said public mobile radio network via saidfirst device; wherein said communications interface module is a separatearticle from said first and second device and is configured tointerengage with said second device to provide electrical connection forelectronic communication between said communications interface moduleand said second device, said electrical connection comprising a part ofsaid communications conduit; and further wherein said communicationsinterface module comprises a local network communications module forestablishing a communications connection between said first device andsaid communications interface module, said communications connectioncomprising a remaining part of said communications conduit; wherein saidfirst device is configured to: determine network information from acentral network application for at least one of said public mobile radionetwork and said private mobile radio network; retrieve informationconcerning one or more network capabilities from said second device viasaid communications interface module; select said one or other of saidpublic mobile radio network or said private mobile radio network fortransmitting or receiving said communication based on at least one ofsaid one or more network capabilities, respective geographic locations,and said network information; and communicate a location fix torespective network applications over a selected one of said publicmobile radio network or said private mobile radio network.
 2. Thecommunications assembly of claim 1, wherein said communicationsinterface module is configured to provide a secure communicationsconduit between said first and second devices over said localcommunications medium.
 3. The communications assembly of claim 1,wherein said first device is configured to determine said one or morenetwork capabilities of respective said private mobile radio network. 4.The communications assembly of claim 1, wherein said first device isconfigured to determine said one or more network capabilities ofrespective said private mobile radio network; wherein said one or morenetwork capabilities include one or more of the following: signalquality, communications capability and bandwidth; and wherein locationinformation for respective first and second devices is compared on saidfirst device to identify said location fix.
 5. The communicationsassembly of claim 1, wherein said first device is configured to providea second device communications inhibit signal to said communicationsinterface module responsive to selection of said public mobile radionetwork for communications, said communications interface moduleresponsive to said second device communications inhibit signal toinhibit communication via said second device and private mobile radionetwork.
 6. The communications assembly of claim 5, wherein saidcommunications interface module is responsive to said second devicecommunications inhibit signal to inhibit an impedance change on amicrophone circuit of said second device.
 7. A communications assembly,comprising: a first device communicatively coupled to a public mobileradio network; a second device communicatively coupled to a privatemobile radio network; and a communications interface module configuredto provide a communications conduit between said first and seconddevices over a local communications medium for routing: a communicationoriginating at said first device through said communications interfacemodule for transmission over said private mobile radio network via saidsecond device; and a communication initiated at said communicationsinterface module for transmission over said public mobile radio networkvia said first device; wherein said communications interface module is aseparate article from said first and second device and is configured tointerengage with said second device to provide electrical connection forelectronic communication between said communications interface moduleand said second device, said electrical connection comprising a part ofsaid communications conduit; and further wherein said communicationsinterface module comprises a local network communications module forestablishing a communications connection between said first device andsaid communications interface module, said communications connectioncomprising a remaining part of said communications conduit; wherein saidfirst device is configured to determine one or more network capabilitiesof respective said private mobile radio network; wherein said one ormore network capabilities include one or more of the following: signalquality, communications capability and bandwidth; and wherein said firstdevice is configured to: retrieve information concerning said one ormore network capabilities from said second device via saidcommunications interface module; and select said one or other of saidpublic mobile radio network or said private mobile radio network fortransmitting or receiving said communication based on at least one ofsaid one or more network capabilities, respective geographic locations,and said network information; wherein said first and second device areconfigured to periodically determine at least one of said one or morenetwork capabilities and said geographic location to provide updatedinformation thereon; wherein said first device is configured to selectsaid one or other of said public mobile radio network and said privatemobile radio network for communications based on said updatedinformation; and wherein said first device is configured to periodicallydetermine said network information to provide updated networkinformation and select said one or other of said public mobile radionetwork and said private mobile radio network based on said updatednetwork information.
 8. The communications assembly of claim 7, whereinsaid communications interface module is configured to provide a securecommunications conduit between said first and second devices over saidlocal communications medium.
 9. The communications assembly of claim 7,wherein location information for respective first and second devices iscompared on said first device to identify a location fix.
 10. Thecommunications assembly of claim 7, wherein said first device isconfigured to provide a second device communications inhibit signal tosaid communications interface module responsive to selection of saidpublic mobile radio network for communications, said communicationsinterface module responsive to said second device communications inhibitsignal to inhibit communication via said second device and privatemobile radio network.
 11. The communications assembly of claim 10,wherein said communications interface module is responsive to saidsecond device communications inhibit signal to inhibit an impedancechange on a microphone circuit of said second device.
 12. Acommunications assembly, comprising: a first device communicativelycoupled to a public mobile radio network; a second devicecommunicatively coupled to a private mobile radio network; and acommunications interface module configured to provide a communicationsconduit between said first and second devices over a localcommunications medium for routing: a communication originating at saidfirst device through said communications interface module fortransmission over said private mobile radio network via said seconddevice; and a communication initiated at said communications interfacemodule for transmission over said public mobile radio network via saidfirst device; wherein said communications interface module is a separatearticle from said first and second device and is configured tointerengage with said second device to provide electrical connection forelectronic communication between said communications interface moduleand said second device, said electrical connection comprising a part ofsaid communications conduit; and further wherein said communicationsinterface module comprises a local network communications module forestablishing a communications connection between said first device andsaid communications interface module, said communications connectioncomprising a remaining part of said communications conduit; wherein saidfirst device is configured to determine one or more network capabilitiesof respective said private mobile radio network; wherein said one ormore network capabilities include one or more of the following: signalquality, communications capability and bandwidth; and wherein said firstdevice is configured to: retrieve information concerning said one ormore network capabilities from said second device via saidcommunications interface module; and select said one or other of saidpublic mobile radio network or said private mobile radio network fortransmitting or receiving said communication based on at least one ofsaid one or more network capabilities, respective geographic locations,and said network information; wherein said first device is configured tocommunicate information identifying at least one of said selected one ofsaid public mobile radio network and said private mobile radio networkto central network applications.
 13. The communications assembly ofclaim 12, wherein said communications interface module is configured toprovide a secure communications conduit between said first and seconddevices over said local communications medium.
 14. The communicationsassembly of claim 12, wherein location information for respective firstand second devices is compared on said first device to identify alocation fix.
 15. The communications assembly of claim 12, wherein saidfirst device is configured to provide a second device communicationsinhibit signal to said communications interface module responsive toselection of said public mobile radio network for communications, saidcommunications interface module responsive to said second devicecommunications inhibit signal to inhibit communication via said seconddevice and private mobile radio network.
 16. The communications assemblyof claim 15, wherein said communications interface module is responsiveto said second device communications inhibit signal to inhibit animpedance change on a microphone circuit of said second device.